[Objective] The evolution characteristics and driving factors of water-related ecosystem services(WRESs) in Hebei Province under land use and land cover change(LUCC) and climate change(CC) scenarios in the future were quantitatively evaluated, and their multiscale uncertainties were revealed, in order to provide a scientific basis for regional water ecosystem management. [Methods] This study integrated the MRI-ESM2-0 climate model, the future land use simulation(FLUS) model, and the integrated valuation of ecosystem services and tradeoffs(InVEST) model to evaluate the integrated effects of CC and LUCC on water conservation(WC) and soil erosion(SE) in Hebei Province, and to reveal their multiscale uncertainties. [Results] From 2024 to 2050, WC in Hebei Province showed an overall upward trend under both climate scenarios. Under the SSP245 scenario, WC increased first and then stabilized, while it continuously increased under SSP585. SE exhibited an overall declining trend, decreasing steadily under SSP245 but first increasing and then decreasing under SSP585. CC played a dominant role in influencing WRESs, with its contributions to WC and SE reaching up to 99.30% and 93.14%, respectively. However, its influence gradually weakened over time. The contribution of LUCC to WC declined over time, while its contribution to SE, though smaller, gradually increased. Uncertainty driven by CC was generally higher than that driven by LUCC, and overall uncertainty decreased over time across all scales. [Conclusion] Water-related ecosystem services in Hebei Province are projected to show an overall trend of “enhanced water conservation and reduced soil erosion”. The synergistic effects of climate humidification and ecological protection significantly improve regional hydrological regulation and ecological stability. Strengthening ecological restoration and implementing zonal management are key pathways to enhance regional water security and mitigate climate risks.